Rate-sensing tuning fork design

• US 5,476,008 A
• Filed: 07/25/1994
• Issued: 12/19/1995
• Est. Priority Date: 07/25/1994
• Status: Expired due to Fees

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Rockwell International Corporation
• Inventors: Pinson, John C.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/279,722
• Time in Patent Office: 512 Days
• Field of Search: 73/505, 310/321, 310/323, 310/326, 310/327, 310/329, 310/330, 310/370, 310/367
• US Class Current: 73/504.16
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719

Abstract

An improvement in rate-sensing tuning fork design includes a generally planar and H-shaped sensor frame of piezoelectric material. The frame includes a first pair of tines and a second pair of tines joined to an intermediate cross-piece. Connecting means is provided for connecting each of the second pair of tines to the other of said second pair at a location spaced from said intermediate cross-piece. The connecting means is preferably a connecting member formed of piezoelectric material, with the member being generally parallel to the intermediate cross-piece of the H-shaped frame and disposed between the second pair of tines. The connecting means prevents each of the tines of the second pair from vibrating directly toward or away from each other. A preferred method of use of the device is described.

Claims

1. In a rotation rate sensor of the type that includes a generally planar and H-shaped sensor frame of piezoelectric material, said frame including a first pair of tines and a second pair of tines collectively forming legs of said H-shape, each of said first and second pairs of tines being joined to an intermediate cross-piece, the first pair of tines, the second pair of tines, and the intermediate cross-piece defining a planar configuration, the frame further including a first array of drive electrodes fixed to said first pair of tines for transmitting electrical signals for driving said first pair of tines in-plane, and a second array of pickoff electrodes fixed to said second pair of tines for transmitting electrical signals generated in said second pair of tines in response to Coriolis-induced out-of-plane bending thereof, the improvement comprising:

connecting means for connecting each tine of the second pair of tines to the other tine of said second pair of tines at a location spaced from said intermediate cross-piece, toward the tine ends of the second pair of tines.

2. The sensor of claim 1, wherein said connecting means comprises a connecting member of piezoelectric material that is generally parallel to said intermediate cross-piece.

3. The sensor of claim 1 or claim 2, wherein said connecting means is disposed between said second pair of tines to prevent each tine of said second pair of tines from vibrating directly toward and away from each other.

4. A method of sensing rotation, including the steps of:

vibrating a first pair of piezoelectric tines at a first frequency;

coupling a second pair of tines to the first pair of tines, the second pair of tines being parallel to and interconnected with said first pair of tines;

connecting the tines of the second pair of tines to each other to prevent vibration of each tine of the second pair of tines toward and away from each other; and

sensing piezoelectric voltages in said second pair of tines, said voltages in said second pair of tines being induced by the vibration of said second pair of tines, which vibration is in turn caused by the vibration of said first pair of tines and the rotation of said first and second pairs of interconnected tines.

5. A sensor comprising:

a generally planar and H-shaped sensor frame of piezoelectric material, said frame including a first pair of tines and a second pair of tines, the first and second pairs of tines joined by an intermediate cross-piece;

connecting means for connecting each tine of the second pair of tines to the other tine of the second pair of tines at a location spaced away from said intermediate cross-piece, toward the tine ends of the second pair of tines,

wherein said connecting means is disposed between the second pair of tines to prevent each tine of the second pair of tines from vibrating directly toward and away from each other.

6. A rotation rate sensor including a first pair of tines and a second pair of tines, the pairs of tines being joined by an intermediate cross-piece, the pairs of tines and the cross-piece being of piezoelectric material, and further including connecting means for connecting each tine of the second pair of tines to the other tine of the second pair at a location spaced apart from said intermediate cross-piece, wherein the connecting means is disposed between each tine of the second pair of tines to prevent the tines from vibrating toward and away from each other.

7. The sensor of claim 6, wherein said connecting means comprises a connecting member of piezoelectric material that is generally parallel to the intermediate cross-piece.

8. An angular rate sensor, including:

a dual tuning fork structure of piezoelectric material, each of the tuning forks having a pair of tines and a base portion, the dual tuning forks being interconnected at said base portions;

an attachment member for attaching one tine of one of the pairs of tines to the other tine of the pair at a location remote from the interconnected base portions,

wherein the attachment member is substantially parallel to the interconnected base portions, and the tuning forks are disposed in oppositely extending directions from said interconnected base portions along a first axis,

further wherein the tines of each pair of tines are spaced relatively to each other along a second axis perpendicular to the first axis, such that the attachment member prevents the two attached tines of the pair of tines from moving relative to each other along the second axis.